Abstract

Ferroelectric HfO2thin films 10 nm thick are simultaneously doped with Al and Si. The arrangement of the Al and Si dopant layers within the HfO2 greatly influences the resulting ferroelectric properties of the polycrystalline thin films. Optimizing the order of the Si and Al dopant layers led to a remanent polarization of ∼20 μC/cm2 and a coercive field strength of ∼1.2 MV/cm. Post-metallization anneal temperatures from 700 °C to 900 °C were used to crystallize the Al and Si doped HfO2thin films. Grazing incidence x-ray diffraction detected differences in peak broadening between the mixed Al and Si doped HfO2thin films, indicating that strain may influence the formation of the ferroelectric phase with variations in the dopant layering. Endurance characteristics show that the mixed Al and Si doped HfO2thin films exhibit a remanent polarization greater than 15 μC/cm2 up to 108 cycles.

This work was supported in part by the NSF I/UCRC on Multi-functional Integrated System Technology (MIST Center) IIP-1439644. P.L. is the recipient of a SRC Graduate Fellowship, and J.J. acknowledges support from NSF under DMR-1207293 (J.J., C.Z.). The authors acknowledge the use of the Analytical Instrumentation Facility (AIF) at North Carolina State University, which was supported by the State of North Carolina and the National Science Foundation.